SpikeVax's Vaccine Effectiveness Decreases Quickly

The peer-reviewed journal Nature Medicine published a study on February 21, 2022, that 3-doses of Modern'a SpikeVax vaccine's effectiveness (VE) against hospitalization caused by the SARS-CoV-2 virus variants Delta or Omicron was about 99% across the entire study population.

However, the mRNA COVID-19 VE decreased quickly.

SpikeVax (mRNA-1273) was 71.6% (69.7–73.4%) at 14–60 days and 47.4% (40.5–53.5%) effective against Omicron infection after 60 days.

Furthermore, SpikeVax's 3-dose VE was just 29.4% (0.3–50.0%) against Omicron infection in immunocompromised individuals. 

This research was led by a Kaiser Permanente Southern California team that conducted a test-negative case-control study among 26,683 COVID-19 cases caused by the Delta and/or Omicron infections in December 2021.

This study's correspondence is Hung Fu Tseng @[email protected].